Memory
A digital camera stores all of the photos it takes on a memory card.

• Compact flash card, Smart Media cards

By far the most popular and least expensive is the Compact flash. Memory cards come in different sizes, generally the larger they are the more photos they will hold. However the amount a particular cameras memory card will hold will depend of the size of the photos and compression.
Compression
Compression is how much the digital camera compresses an image. When a digital camera takes a picture, a very large file is created . In order to fit more images on a memory card, digital cameras compress these image files.

The camera might have different settings like Small, Good, Fine or best all will produce a photo that has a different quality, and different photo size. The cameras resolution setting will also influence the quality of the final picture.

The more expensive digital cameras will have their own LCD display, which you can preview the picture on, or view what you are about to take a photo of, but be aware that these displays also take more power, and the cameras battery wont last as long as it would without previewing.